diff --git a/packages/core/src/utils/compatibility.test.ts b/packages/core/src/utils/compatibility.test.ts
index 23597e0c7a..dfa9ffb14f 100644
--- a/packages/core/src/utils/compatibility.test.ts
+++ b/packages/core/src/utils/compatibility.test.ts
@@ -108,6 +108,7 @@ describe('compatibility', () => {
     });
 
     it('should return false when TMUX is not set', () => {
+      vi.stubEnv('TMUX', '');
       expect(isTmux()).toBe(false);
     });
   });
@@ -119,6 +120,7 @@ describe('compatibility', () => {
     });
 
     it('should return false when STY is not set', () => {
+      vi.stubEnv('STY', '');
       expect(isGnuScreen()).toBe(false);
     });
   });
@@ -166,22 +168,35 @@ describe('compatibility', () => {
     });
 
     it('should use JETBRAINS_IDE if TERM_PROGRAM is missing', () => {
+      vi.stubEnv('TERM_PROGRAM', '');
       vi.stubEnv('TERMINAL_EMULATOR', 'JetBrains-JediTerm');
       vi.stubEnv('JETBRAINS_IDE', 'PyCharm');
       expect(getTerminalNameFromEnv()).toBe('PyCharm');
     });
 
     it('should use TMUX if other vars are missing', () => {
+      vi.stubEnv('TERM_PROGRAM', '');
+      vi.stubEnv('TERMINAL_EMULATOR', '');
+      vi.stubEnv('JETBRAINS_IDE', '');
       vi.stubEnv('TMUX', 'some-socket');
       expect(getTerminalNameFromEnv()).toBe('tmux');
     });
 
     it('should use STY if other vars are missing', () => {
+      vi.stubEnv('TERM_PROGRAM', '');
+      vi.stubEnv('TERMINAL_EMULATOR', '');
+      vi.stubEnv('JETBRAINS_IDE', '');
+      vi.stubEnv('TMUX', '');
       vi.stubEnv('STY', 'some-session');
       expect(getTerminalNameFromEnv()).toBe('GNU screen');
     });
 
     it('should return Unknown if no vars are set', () => {
+      vi.stubEnv('TERM_PROGRAM', '');
+      vi.stubEnv('TERMINAL_EMULATOR', '');
+      vi.stubEnv('JETBRAINS_IDE', '');
+      vi.stubEnv('TMUX', '');
+      vi.stubEnv('STY', '');
       expect(getTerminalNameFromEnv()).toBe('Unknown');
     });
   });